Co-owned U.S. Pat. No. 4,419,100 discloses an ostomy appliance
of two main parts detachably connected by a pair of semi-rigid coupling rings. One part consists of a pouch on which one of the coupling rings is mounted, the other takes the form of a faceplate to which the other of the rings is connected by means of a flexible annular web. The web allows limited floating action between the second coupling ring and the faceplate, thereby facilitating attachment and detachment of the rings without causing wearer discomfort and allowing conformity of the flexible faceplate to a wearer's body without objectionable resistance from the semi-rigid rings.
U.S. Pat. No. 4,834,731 discloses an ostomy appliance having a convex pressure ring assembly and, in one embodiment (FIG. 7) a web is also utilized to connect a faceplate, in which a convex pressure ring is provided, with a semi-rigid coupling ring, thereby utilizing the floating ring feature of the first-mentioned patent. Both patents also disclose that the faceplates may be formed largely of gas-penetrable, but water-resistant microporous sheet material. Reference is made to co-owned U.S. Pat. No. 4,213,458 which also shows and describes microporous faceplate constructions with particular emphasis on the coactive use of a thin, flexible attaching ring for securing a microporous faceplate to a pouch in a manner that converts peeling forces to shearing forces and thereby reduces the possibilities that the microporous faceplate might become torn in use.
A microporous faceplate is considered superior to a non-porous faceplate because it does not prevent cutaneous respiration and, since water vapor is allowed to escape, such a faceplate may remain in place for longer intervals without tissue necrosis and other complications. A gas-permeable pressure-sensitive adhesive is used to secure such a faceplate to the peristomal surfaces of the skin. While conventional adhesives used for that purpose are not water-soluble in the ordinary sense, they are degraded by contact with water and we have found that with some microporous faceplate constructions there is a risk that stomal fluid may wick through the microporous matrix and adversely affect the adhesive seal. Moreover, if such conditions exist, then there is also the possibilities of fluid leakage in planar pathways through the microporous material of a faceplate, an obviously undesirable circumstance.
An important aspect of this invention therefore lies in providing a microporous faceplate construction which achieves the advantages of prior constructions, including the advantages disclosed in some or all of the aforementioned patents, while at the same time providing an improved construction for insuring that the inner margin of a microporous ring will remain isolated from contact with stomal fluid when the ostomy appliance is in use. In addition to its durability and outstanding leak-resistant properties, such a construction may also provide additional advantages such as, for example, increasing the "floating" action of a faceplate coupling ring, thereby increasing security, patient comfort and ease of attachment.
Briefly, the ostomy appliance includes a collection pouch formed of plastic film having a wall provided with a stoma opening. A flexible and generally planar faceplate is provided for adhesively attaching the pouch to the peristomal skin surfaces of a wearer. In its simplest form, the faceplate includes an outer ring of thin, microporous sheet material and an inner ring formed of a thermoplastic film that is impervious to gases and body fluids. The rings have coaxial openings aligned with the stoma opening of the pouch with the opening of the microporous ring being substantially larger than that of the inner impervious ring. The impervious inner ring has its proximal or bodyside surface along its outer margin secured to the distal surface of the microporous ring adjacent its inner margin. An adhesive barrier ring is secured to the proximal surface of the microporous ring and extends radially inwardly from the inner margin of the microporous ring, and a fluid-impervious annular seal is provided between the proximal surface of the inner ring and the inwardly-extending portion of the barrier ring for securing such rings together and for isolating the inner margin of the microporous ring, and the pressure-sensitive adhesive layer on the proximal surface of that ring, from contact by stomal fluids.
In different embodiments of the invention, the seal may take the form of a sealant ring or of an annular heat seal. If a sealant ring is provided, it may also sealingly and adhesively engage the microporous ring along its inner margin. Most advantageously, the seal is spaced a substantial distance radially outwardly from the inner margin of the impervious inner ring. A sealant ring is preferably formed of a hot melt sealant, particularly one that is deformable and elastically recoverable.
Where the sealant ring is spaced a substantial distance radially outwardly from the inner margin of the impervious inner ring, that inner margin may be sealed to the inner portion of an annular thermoplastic web which in turn has its outer margin attached to a relatively rigid (or semi-rigid) faceplate coupling ring. That coupling ring is therefore connected to the faceplate in a "floating" relationship that permits a user to insert his/her fingers between the two during a coupling operation. The floating ring construction performs a major function in allowing the flexible faceplate to conform with the contours of a wearer's body without resistance from the relatively rigid coupling ring(s) attached to that faceplate.
In one form of the invention the barrier ring, in addition to including a layer of soft, deformable, moisture-absorbing skin barrier material having both wet and dry tack, has a layer of soft liquid and gas impermeable thermoplastic foam (or other thermoformable material) and a relatively rigid convex pressure ring positioned with its convex surface facing proximally and contacting the thermoplastic foam. In such a construction, the adhesive sealant ring or annular heat seal may also engage or include the distal surface of the convex pressure ring to provide a secure bond between the different rings of the faceplate.
Other features, objects, and advantages will become apparent from the specification and the drawings.